1. Field of the Invention
This invention relates to a structure of the watch case wherein a case body having a time display section rotates with respect to a band attaching base, particularly a rotating mechanism for the watch case.
2. Prior Art
A conventional structure of a rotating case of this type is disclosed in the specification of Japanese Utility Model Application Laid-Open No. 59-98385.
As shown in FIG. 19, the conventional structure includes an upper middle 10 internally accommodating a time display section having a dial, hands, movement and the like, a lower middle 12 to which a band 14 is attached, and a back cover 16 screwed securely and water-tightly into the upper middle 10 via a packing 18. The lower middle 12 is rotatably sandwiched between the upper middle 10 and the back cover 16. Further, the packing 20 is interposed between the back cover 16 and the lower middle 12 to get a suitable regulation of the rotation by friction produced between the back cover 16 and the packing 20.
In the prior art, in order to position the packing 20, a recess 16a is formed in the outer circumferential surface of the back cover 16. As a result, a shape of the back cover 16 becomes complicated and its height becomes higher. Further, the back cover 16 cannot be used in common in other watch cases, thus making it impossible to achieve standardization.
As shown in FIG. 20, the conventional structure further includes a hole 10a provided at a lower surface of the upper middle 10, a spring 22 adapted in the hole 10a, a ball 23 pressed by the spring 22 in the direction of the lower middle 12 and radial grooves 12a. The radial grooves 12a are formed at the upper face of the lower middle 12 as shown in FIG. 21. The ball 23 and the grooves 12a are engaged, therefore, when the upper middle 10 is rotated the feeling of a click operation is produced.
In the conventional structure, the upper middle 10 is able to rotate through 360.degree. with respect to the lower middle 12. Consequently, when rotating the upper middle 10, the 12:00 position becomes indistinct. Thus, it is necessary to make the 12:00 indicator to stand out.
A further problem is that it is difficult to select a position at which the upper middle 10 is to be stopped in a case where the click groove structure is operated during the operation of a vehicle or the like.